Bat-Harvester Data Summary

General Site Information

As of March 19, 2019, data on bat guano-harvester interactions is available for 3 countries : Myanmar, Democratic Republic of Congo, Viet Nam. All are PREDICT sites except Kimpese/Weene in the Democratic Republic of Congo.

5 of the 7 sites are at the cave interface, where bat guano is harvested from fecal matter of bats roosting in caves. Only caves were access-controlled, with some sites (Myanmar) primarly functioning as a religious temple, while others required a permit or verbal permission to enter. Other interesting variables for cave sites include cave height, degree of light penetration, degree of water coverage, and ease of cave navigation.

2 of the 7 sites are at the farm interface, where bat guano is harvested from artificial roosts set up below tree-like structures (Fig. 1, below). Both farm sites had artifical roosts composed of sugar palm leaves.

Bats were present during harvest at all sites. Most roosts were 1,000 - 5,000 bats in size, except the Viet Nam cave site where there were over 100,000 bats, potentially as high as 3 million depending on the season.

Fig 2. Roost sizes across sites

Harvesters

The DRC and Vietnam cave sites had the highest number of harvesters, and some of the highest frequencies of harvest. All Viet Nam sites were harvested frequently, both at cave and farm sites.

All harvesters were local in origin, although Myanmar Caves 2 and 3 also had seasonal harvesters come in. Non-harvesters were present at the guano harvesting areas for all sites except the DRC cave; this included locals at all sites, children at all Myanmar sites and at the Viet Nam Cave site, and 10-20 tourists per day at Myanmar Cave 3 (Saddan Cave) site. Limits to harvesting included bat migration elsewhere (5/7 sites), high water levels (2 cave sites), low demand (2 cave sites) , and hunting of bats for food by locals (cave and farm site in Viet Nam).

Activities at all sites included harvesting, packaging, and storing guano. Selling guano also occurred at all Myanmar and Viet Nam sites.

Guano

Sites in Myanmar were harvested the least frequently, ranging from 3 times/month to once a year. Despite this, MMR-Cave-2 (Buffalo Cave) had the highest collection volume at approximately 54,000 kg annually. Collection occured daily or several times a week at the DRC and Viet Nam sites, with volumes ranging from 312 - 3000 kg collected per year.

Exposure and Risk

An exposure risk level was calculated from groupings of exposure variables: Guano Exposures, Collection Exposures, Personal and Protective Equipment (PPE) Exposures, and Water, Sanitation and Hygiene (WASH) Exposures. Each variable was assigned a relative exposure risk level: - Lowest risk: <0.2 - Low risk: 0.2-0.4 - Medium risk: 0.4-0.6 - High risk: 0.6-0.8 - Highest risk: >0.8.

Guano Exposures refer to environmental guano exposures, and are calculated from:

• Guano Area
• Guano Depth
• Bat Roost Size

Collection Exposures are a function of the method that harvesters used to collect the guano - with riskier practices like using hands only to collect guano contributing to a higher exposure value:

• Use of shovel
• Use of spade
• Use of broom
• Use of hands only

PPE Exposures are protective factors related to the wearing of protective equipment and clothing:

• Wearing Gloves
• Wearing Goggles
• Wearing Shoes
• Wearing a Mask or Makeshift Mask
• Wearhing Shoes
• Wearing Clothing specifically for Guano Harvesting

Water, Sanitation, Hygiene factors refer to the availability and use of water and soap for washing and are a summary of the following:

• Washing after harvesting
• Use of soap for washing
• Washing of shoes post guano exposure
• Washing of feet post guano exposure
• Washing of hands post guano exposure
• Washing of body post guano exposure

The DRC site had the highest risk exposure value (0.75) attributed to riskier collection practices such as the use of hands to harvest guano instead of other implements. While Viet Nam Farm Site 2 had the lowest overall risk exposure value (0.44), guano is harvested for approximately 7,300 minutes per year per harvester. Though the Viet Nam Cave Site did not have a particularly high risk exposure value, guano is harvested for 65,700 minutes (1095 hours) per year at a total volume 7,300 kg of guano harvested.

Observations and Notes

Often, though water was not available directly on site for washing, harvesters washed their bodies in nearby rivers (Myanmar Cave Sites 1 and 2, Viet Nam Cave site).Another risky practice not explicitly covered in the questionnaire but derived from responses is eating lunch and snacks in the cave during breaks from harvesting guano.